Methane and carbon dioxide in the enhanced greenhouse effect

Carbon dioxide and methane are greenhouse gases. They absorb some of the infrared radiation emitted by Earth, reducing the rate at which energy escapes to space. This helps keep Earth warm. When their concentrations in the atmosphere rise, this warming effect becomes stronger.

Sources of carbon dioxide and methane

Burning fossil fuels releases carbon dioxide into the air. Deforestation also increases atmospheric carbon dioxide: carbon can be released when cleared vegetation burns or decays, and fewer trees remain to take up carbon dioxide.

Methane is released by sources including livestock and the decay of organic waste. For example, some livestock produce methane during digestion.

How extra greenhouse gases warm Earth

Earth absorbs energy from the Sun and emits some energy as infrared radiation. Carbon dioxide and methane absorb some of this outgoing radiation and emit infrared radiation in all directions, including back towards Earth’s surface. This reduces the rate at which energy escapes to space.

The natural greenhouse effect warms Earth without the additional greenhouse gases from human activities. Higher concentrations of carbon dioxide and methane strengthen this effect. This is the enhanced greenhouse effect, which raises global temperatures.

The enhanced greenhouse effect drives climate change, including changes in temperature and rainfall patterns.